Visitor Visa 6-month rule

[KenBossini]

Hi all,

Apologies if this is a repetition.

Can someone please help me understand the visitor visa 6-month rule? The government website (https://www.gov.uk/standard-visitor-visa) mentions the following:

"If you need to visit the UK regularly over a longer period, you can apply for a long-term Standard Visitor visa that lasts 2, 5 or 10 years. You can stay for a maximum of 6 months on each visit."

However, is that a period of 6 months in a 12-month period?
a. If yes, how is the 12-month period calculated or defined?
b. If no, how long the gap needs to be between two 6-month visits to the UK?

Thanks,
K.

[Casa]

Visitors shouldn't spend more time in the UK within a 12 months rolling period than they are spending in their home country.

[KenBossini]

Visitors shouldn't spend more time in the UK within a 12 months rolling period than they are spending in their home country.

Thanks Casa. Just to be sure, the 12 month rolling period can start on any day for the purpose of the calculation of days spent in the UK?